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<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <script>
        // 什么是高阶函数呢
//         let arr=['哈哈','嘿嘿','呵呵']
//   Array.prototype.forEach1= function (callback) {
//       for(let i=0; i < this.length;i++ ) {
//         //   console.log(this[i])
//           callback(this[i])
//       }
//   }
// arr.forEach1((item) => {
//     console.log(item)
// })
function fn (callback) {
    console.log('哈数')
    callback(12312)
}
 fn ((heo) => {
 console.log(heo+'内部的')
 })
    </script>
</body>
</html>